I'm just a 'tad bit older' than you (LOL) but one thing I found to be helpful to me in becoming a stronger sober person was to think outside the box. All your friends will be going out getting drunk. So...what to do? There is a WORLD of choices out there. Don't just think outside the box -get outside the box. You have to ACT on it. Actually DO something different. I found that changing my every move, my every habit, my every thought was an encouragement to keeping myself sober. Challenge yourself.
I do understand how difficult it will be for you with everyone around you drinking. But that's when you plan an escape route. If you start feeling tempted -bolt. Leave...go for a walk. Grab the nearest dog and walk...go out for ice cream. I could never drink when I had ice cream. Yuck.
I commend you on your efforts and if you stick around here you'll find some great advice and ideas to be strong and grow into your own soul.
Wishing you peace and strength.